Modeling of nociception in an integrated human multi-tissue platform This application is for an Administrative Supplement to the parent grant EB025765: Multi-tissue platform for modeling systemic pathologies, submitted in response to NOT- TR-19-001. In our parent grant, we have established a strong scientific premise for modeling disease and testing of drug safety and efficacy using a human multi-tissue platform. Five tissue systems: heart, liver, skin, bone and vasculature, are grown from the same batch of iPS cells, and perfused with a blood substitute containing circulating immune cells. We demonstrated the maturity and physiologic function for these tissue systems. A key innovation is in the biomimetic approach to functional integration, by (i) maintaining a local regulatory niche for each tissue, (ii) connecting tissue units by a common perfusate containing immune cells, and (iii) establishing endothelial barrier between the vascular and tissue compartments. The platform is modular, configurable, PDMS-free and enables real-time monitoring of cell and tissue functions. Here we propose to incorporate a sensory nerve module into this platform, to enable modeling of nociception and mechanoreception under physiologically relevant conditions. This proposal has been motivated by the difficulties in studying pain in humans, due the subjective factors and ethical considerations, along with the inability to faithfully reproduce the pain responses in animal models. We suggest that the use of bioengineered human tissues as preclinical models of nociception would be transformative for the study and treatment of pain. Our objectives are to: (1) design a patient-specific sensory nerve (SN) module with vascular perfusion; (2) validate the functionality of iPSC-derived SNs against native human dorsal root ganglia; (3) demonstrate the use of methodologies for measuring nociception and touch responses (including the genetic/optogenetic tools for quantification of neuronal responses to painful stimuli; (4) integrate the SN module with the liver module in proof-of-principle experiments of nociception. In Aim 1, we will establish a sensory nerve module with vascular perfusion, generate the nociceptive and ?touch? neurons from human iPSCs, and validate the sensory neurons against the native human neurons from the dorsal root ganglia. In Aim 2, we will develop methodologies for measuring nociception and touch responses, and conduct the proof-of-principle studies of nociception in the integrated sensory neuron-liver platform. Our milestones are: (1) Design and fabricate of the sensory module (3 months); (2) Generate iPSC-SN (6 months); (3) Demonstrate nociception responses (9 months); (4) Integrate the sensory and liver modules for measuring nociception responses (9 months).